In an E-UTRAN mobile communication system, when a mobile station UE connected to a radio base station HeNB (Home eNodeB) operated in a “Hybrid Access” scheme or a “Closed Access” scheme performs an attach process, a service request process, or a handover process, a mobile switching center MME is configured to perform “Accessibility Check” for checking whether the mobile station UE has an access right to a CSG (Closed Subscriber Group) cell subordinate to the radio base station HeNB.
With reference to FIG. 11, an example of the “Accessibility Check” will be simply described.
As illustrated in FIG. 11, a mobile station UE having visited a cell subordinate to a radio base station eNB transmits “Measurement Report (step S1001A)” including only PCI (Physical Cell ID), or “Measurement Report (step S1001B)” including the PCI and E-CGI (E-UTRA Cell Global ID) to the radio base station eNB.
If the radio base station eNB decides a handover of the mobile station UE based on the received “Measurement Report”, the radio base station eNB decides eNB-ID “yyy.001” of a radio base station HeNB2 (a handover destination) based on the PCI (step S1002A) or the
E-CGI (step S1002B) which is included in the “Measurement Report”, and transmits “HO Required” including the eNB-ID “yyy.001” of the radio base station HeNB2 to a mobile switching center MME in step S1003.
In step S1004, the mobile switching center MME extracts CSG-ID “#31” corresponding to the eNB-ID “yyy.001” of the radio base station HeNB2 included in the received “HO Required” with reference to “eNB-ID←→CSG-ID table”, and checks whether the CSG-ID “#31” is included in “UE CSG Subscription info” for the mobile station UE, thereby performing “Accessibility Check” with respect to the mobile station UE.
In addition, the mobile switching center MME is configured to accommodate the “eNB-ID←→CSG-ID table” including a combination (entry) of eNB-ID and CSG-ID of the radio base station HeNB when an S1 connection is established between the mobile switching center MME and each radio base station HeNB.